1. Field of the Invention
The invention relates to a fuel injection device, and to a method of manufacturing the device, for an internal combustion engine with direct fuel injection, the device having a housing and at least two valve elements, located in the housing and coaxial to one another, to each of which at least one fuel outlet opening is assigned, and on the outer valve element, radially outward from the at least one fuel outlet opening assigned to it, there is a first sealing region, which cooperates with a valve seat on the housing and which can separate the at least one fuel outlet opening from a high-pressure connection.
2. Description of the Prior Art
A fuel injection device of the type defined above is known from German Patent Disclosure DE 101 22 241 A1. It has a housing with an outer valve element, in which an inner valve element is guided. Associated with each valve element is a series of fuel outlet openings. Both valve elements are stroke-controlled. This means that they each have a control face which acts in the closing direction and defines a control chamber. In the region of the fuel outlet openings, the valve elements each have pressure faces, which act in the opening direction and define pressure chambers, where at least at some times a high fluid pressure also prevails. The pressure faces and control faces are adapted such that whenever a high pressure prevails in the control chambers, both valve elements are closed. By means of briefly lowering the pressure in the control chamber, the forces operative in the closing direction can be reduced, which leads to an opening of one or both valve elements.
The use of two valve elements, each of which is assigned at least one fuel outlet opening, allows furnishing a small or large total outlet cross section, depending on the quantity of fuel to be injected. This in turn makes it possible to inject even comparatively small fuel quantities at high injection pressure, so that in these cases, good atomization of the fuel is attained. At the same time, high fuel quantities can be injected without requiring very long injection times to do so.
The object of the present invention is to refine a fuel injection device of the type defined at the outset such that it has as long a service life as possible, and the engine driven with it has good emissions performance.
This object is attained in that on the outer valve element, between the at least one fuel outlet opening assigned to it and the inner valve element, there is an additional sealing region.